How to pass arguments to pytest if pytest is run programmatically from another module?

Question

In the following example, how do I pass args of run_tests() to pytest.main(...) so that I can use args for the test methods of TestFooBar in test_module.py?

my_module.py

def run_tests(args):
    # How do I pass parameter 'args' to pytest here.
    pytest.main(['-q', '-s', 'test_module.py::TestFooBar'])

test_module.py

class TestFooBar():

    # How do I get 'args' of 'run_tests()' from 'my_module.py' here.

    @pytest.mark.parametrize("args", [args])
    def test_something(args):
       assert 'foo' == args['foo']

    @pytest.mark.parametrize("args", [args])
    def test_something_else(args):
        assert 'bar' == args['bar']

Answer 1

If you execute pytest.main the you are doing the equivalent to calling py.test from the command line, so the only way to pass arguments that I am aware of is via a command line parameter. For this to be possible, your parameters need to be convertable to and from string.

Basically this means creating a conftest.py with the following

def pytest_addoption(parser):
    parser.addoption('--additional_arguments', action='store', help='some helptext')

def pytest_configure(config):
    args = config.getoption('additional_arguments')

Now do something with args: deserialize it, make it a global variable, make it a fixture, anything you want. Fixtures from conftest.py will be available to the entire test.

Needless to say that your call should now include the new parameter:

pytest.main(['-q', '-s', '--additional_arguments', args_string, 'test_module.py::TestFooBar'])